identifier, 1 through 5,663
1 through 5, each 4 months long
=1 if in labor force
=1 if black
years of schooling, period 1
in years, period 1
age^2
number children < 18
husband's monthly income, $
=1 if period == 1
=1 if period == 2
=1 if period == 3
=1 if period == 4
=1 if period == 5
log(hinc)